Authorities have warned residents near the Carlisle River fire in Victoria's Otway Ranges that emergency services may not be able to help anyone who chooses to stay.
It some cases, they say it may be too late to leave and people should take shelter.
The state is sweltering through its worst heatwave since 2009, with temperatures soaring above 40C, potentially smashing records.
At least three homes have been lost in the raging Otways fire, although it's not clear if they are primary residences or holiday homes.
A strong "punchy" wind change is moving through the region, creating erratic and extreme conditions.
"That fire will run. It will develop a plume and it will pick up really significant energy," Forest Fire Management Victoria chief fire officer Chris Hardman said.
Residents living in of Gellibrand, Barongarook, Barongarook West, Kawarren, Carlisle River, Gerangamete have been told to shelter now.
The fire is burning in a northeasterly direction towards Gellibrand, and is threatening homes and lives.
CFA chief officer Jason Heffernan confirmed the fire had broken containment lines with the change.
"(Residents) are getting those winds as predicted by the bureau, and that situation is very dynamic and changing minute by minute," Mr Heffernan told the ABC.
Another emergency warning has been issued for a fire near Camperdown in the state's southwest.
Residents in Kariah, Larralea, Leslie Manor, Lismore, Taaraak should shelter indoors immediately.
Electricity distributor Powercor says its emergency response plan has been activated, with crews monitoring impacts from the fires.
The Carlisle River fire is threatening two major distribution powerlines that supply the region.
More than 15,000 people have been affected by outages, most of them on the Powercor (9068) network in the state's southwest.
"If bushfires damage or destroy parts of the power network, this will affect power supply to properties and impact equipment that relies on electricity such as electric water pumps," network emergency manager Ben Hallet said.
Powercor is working with firefighters to dump fire retardant over large areas of powerlines in the region, while also sending a back-up generator to the coastal town of Apollo Bay.
There are a several watch and act warnings in place for the Walwa fire, near the NSW border, which has been burning for weeks.
Another blaze is burning out-of-control in the state's southwest, with a watch and act message issued for Balmoral, Hynes, Kanagulk, Rocklands, Telangatuk East.
A total fire ban remains current for Victoria on Tuesday, and has been declared for the Wimmera and North East districts on Wednesday.
A community fire refuge is located at the Otway CFA Fire Station as a last resort option for residents, although there's no guarantee the route there will be safe.
Relief centres are open at multiple locations in the region, including Colac Showgrounds, Colac Blue Water Leisure Centre and Grovedale Community Hub.
23°C